/*
 * Copyright 2025 LinQingYing. and contributors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *
 * The use of this source code is governed by the Apache License 2.0,
 * which allows users to freely use, modify, and distribute the code,
 * provided they adhere to the terms of the license.
 *
 * The software is provided "as-is", and the authors are not responsible for
 * any damages or issues arising from its use.
 *
 */

package org.cangnova.cangjie.types

import org.cangnova.cangjie.descriptors.TypeAliasDescriptor
import org.cangnova.cangjie.descriptors.TypeParameterDescriptor

class TypeAliasExpansion private constructor(
    val parent: TypeAliasExpansion?,
    val descriptor: TypeAliasDescriptor,
    val arguments: List<TypeProjection>,
    val mapping: Map<TypeParameterDescriptor, TypeProjection>
) {
    fun getReplacement(constructor: TypeConstructor): TypeProjection? {
        val descriptor = constructor.declarationDescriptor
        return if (descriptor is TypeParameterDescriptor)
            mapping[descriptor]
        else
            null
    }

    fun isRecursion(descriptor: TypeAliasDescriptor): Boolean =
        this.descriptor == descriptor || (parent?.isRecursion(descriptor) ?: false)

    companion object {
        fun create(
            parent: TypeAliasExpansion?,
            typeAliasDescriptor: TypeAliasDescriptor,
            arguments: List<TypeProjection>
        ): TypeAliasExpansion {
            val typeParameters = typeAliasDescriptor.typeConstructor.parameters.map { it.original }
            val mappedArguments = typeParameters.zip(arguments).toMap()
            return TypeAliasExpansion(parent, typeAliasDescriptor, arguments, mappedArguments)
        }

        fun createWithFormalArguments(typeAliasDescriptor: TypeAliasDescriptor) =
            create(null, typeAliasDescriptor, emptyList())
    }
}
